The Moloney murine sarcoma virus specific P60 polyprotein contains p30, p15 and p12 polypeptides and is phosphorylated in transformed cells independent of virus assembly. Phosphorylation occurs in both threonine and serine residues of the p12 moiety of the polyprotein. P60 binds to single-stranded nucleic acids and can be isolated from cells by single-strand DNA sepharose chromatography. Herpes simplex virus cellular RNA sequences can be enriched for and isolated from an excess of cellular RNA sequences by hybridization to denatured viral DNA immobilized on sepharose. A DNA transfection assay has been developed using a combination of the calcium phosphate and DEAE dextran techniques and employs unique transfer of the transfected layer to susceptible indicator layer. BIBLIOGRAPHIC REFERENCES: Robey, W.G., Graham, B.J., Harris, C.L., Madden, M.J., Pearson, G.F. and Vande Woude, G.F.: Persistent herpes simplex virus infections established in two Burkitt lymphoma derived cell lines. J. Gen. Virol. 31:51-62, 1976. Robey, W.G., Oskarsson, M.K., Vande Woude, G.F., Naso, R.B., Arlinghaus, R.B., Haapala, D.K., and Fischinger, P.J.: Cells transformed by certain strains of Moloney sarcoma virus contain murine P60. Cell 10: 79-89, 1977.